(a) One factor negative, so product is negative. $4 \times 3$ = 12, so answer is −12. (b) Both factors negative, so product is positive. $6 \times 3$ = 18. (c) Both factors negative, so product is positive. $5 \times 1$ = 5. (d) One factor negative, so product is negative. $8 \times 4$ = 32, so answer is −32. (e) One factor negative, so product is negative. $9 \times 10$ = 90, so answer is −90. (f) One factor negative, so product is negative. $10 \times 17$ = 170, so answer is −170.